A cup-shaped polishing brush is known in which the base end portions of a plurality of wire-shaped grinding elements arranged annularly are held by a grinding element holder. In such a polishing brush, when the polishing brush is rotated in polishing work, the tip ends of the wire-shaped grinding elements extending in the direction of the axis of center of rotation spread outward due to centrifugal force, and the contact position of the wire-shaped grinding elements on the workpiece becomes unstable. The polishing brush described in Patent Literature 1, therefore, is provided with a grinding element holder and a skirt (tubular member) covering the portions on the polishing holder side of the wire-shaped grinding elements on the outer peripheral side. The skirt prevents the spread of the wire-shaped grinding elements outward during rotation.